Companies formalize their software processes as a way of organizing their development projects. As each project has its own requirements and objectives, a family of processes is required in practice, in order to ensure that each project is handled appropriately. This family may be a collection of predefined processes, but can also be automatically generated by tailoring a general process to a project's context which requires formalization and tool support to be successful. Model-driven engineering provides a formal framework for defining the models and transformations required for automated process tailoring, but various types of models must be specified and evolved, limiting the industrial adoption of this approach. To address this problem, in this paper we propose a megamodel for automated process tailoring. Megamodeling provides an integrating framework for modeling in the large, including the definition and evolution of all models and transformations required for tailoring while hiding complexity. We report the application of our approach to the software development process of Rhiscom, a small Chilean company.